cc: Always use SetNeedsBeginFrame to request the next BeginFrame

cc/output/output_surface_unittest.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/output/output_surface.h"
 
 #include "base/test/test_simple_task_runner.h"
 #include "cc/debug/test_context_provider.h"
 #include "cc/debug/test_web_graphics_context_3d.h"
 #include "cc/output/managed_memory_policy.h"
@@ skipping 192 matching lines @@
   // BeginFrame should be called on the first tick.
   task_runner->RunPendingTasks();
   EXPECT_EQ(client.begin_frame_count(), 1);
   EXPECT_EQ(output_surface.pending_swap_buffers(), 0);
 
   // BeginFrame should not be called when there is a pending BeginFrame.
   task_runner->RunPendingTasks();
   EXPECT_EQ(client.begin_frame_count(), 1);
   EXPECT_EQ(output_surface.pending_swap_buffers(), 0);
 
-  // DidSwapBuffers should clear the pending BeginFrame.
+  // SetNeedsBeginFrame should clear the pending BeginFrame after
+  // a SwapBuffers.
   output_surface.DidSwapBuffersForTesting();
+  output_surface.SetNeedsBeginFrame(true);
   EXPECT_EQ(client.begin_frame_count(), 1);
   EXPECT_EQ(output_surface.pending_swap_buffers(), 1);
   task_runner->RunPendingTasks();
   EXPECT_EQ(client.begin_frame_count(), 2);
   EXPECT_EQ(output_surface.pending_swap_buffers(), 1);
 
   // BeginFrame should be throttled by pending swap buffers.
   output_surface.DidSwapBuffersForTesting();
+  output_surface.SetNeedsBeginFrame(true);
   EXPECT_EQ(client.begin_frame_count(), 2);
   EXPECT_EQ(output_surface.pending_swap_buffers(), 2);
   task_runner->RunPendingTasks();
   EXPECT_EQ(client.begin_frame_count(), 2);
   EXPECT_EQ(output_surface.pending_swap_buffers(), 2);
 
   // SwapAck should decrement pending swap buffers and unblock BeginFrame again.
   output_surface.OnSwapBuffersCompleteForTesting();
   EXPECT_EQ(client.begin_frame_count(), 2);
   EXPECT_EQ(output_surface.pending_swap_buffers(), 1);
@@ skipping 44 matching lines @@
   // BeginFrames...
   output_surface.BeginFrameForTesting();
   EXPECT_EQ(client.begin_frame_count(), 1);
   // ...and retroactively triggered by a SetNeedsBeginFrame.
   output_surface.SetNeedsBeginFrame(true);
   EXPECT_EQ(client.begin_frame_count(), 2);
   // ...or retroactively triggered by a Swap.
   output_surface.BeginFrameForTesting();
   EXPECT_EQ(client.begin_frame_count(), 2);
   output_surface.DidSwapBuffersForTesting();
+  output_surface.SetNeedsBeginFrame(true);
   EXPECT_EQ(client.begin_frame_count(), 3);
   EXPECT_EQ(output_surface.pending_swap_buffers(), 1);
 
   // Optimistically injected BeginFrames should be by throttled by pending
   // swap buffers...
   output_surface.DidSwapBuffersForTesting();
+  output_surface.SetNeedsBeginFrame(true);
   EXPECT_EQ(client.begin_frame_count(), 3);
   EXPECT_EQ(output_surface.pending_swap_buffers(), 2);
   output_surface.BeginFrameForTesting();
   EXPECT_EQ(client.begin_frame_count(), 3);
   // ...and retroactively triggered by OnSwapBuffersComplete
   output_surface.OnSwapBuffersCompleteForTesting();
   EXPECT_EQ(client.begin_frame_count(), 4);
 }
 
 TEST(OutputSurfaceTest, RetroactiveBeginFrameDoesNotDoubleTickWhenEmulating) {
@@ skipping 99 matching lines @@
 
   // 0 bytes limit should be ignored.
   policy.bytes_limit_when_visible = 0;
   context_provider->SetMemoryAllocation(policy,
                                         discard_backbuffer_when_not_visible);
   EXPECT_EQ(1234u, client.memory_policy().bytes_limit_when_visible);
 }
 
 }  // namespace
 }  // namespace cc